/* zpipe.c: example of proper use of zlib's inflate() and deflate()
   Not copyrighted -- provided to the public domain
   Version 1.4  11 December 2005  Mark Adler */

   /* Version history:
	  1.0  30 Oct 2004  First version
	  1.1   8 Nov 2004  Add void casting for unused return values
						Use switch statement for inflate() return values
	  1.2   9 Nov 2004  Add assertions to document zlib guarantees
	  1.3   6 Apr 2005  Remove incorrect assertion in inf()
	  1.4  11 Dec 2005  Add hack to avoid MSDOS end-of-line conversions
						Avoid some compiler warnings for input and output buffers
	*/

#include <stdio.h>
#include <string.h>
#include <assert.h>
#include "miniz.h"

#if defined(MSDOS) || defined(OS2) || defined(WIN32) || defined(__CYGWIN__)
#  include <fcntl.h>
#  include <io.h>
#  define SET_BINARY_MODE(file) setmode(fileno(file), O_BINARY)
#else
#  define SET_BINARY_MODE(file)
#endif

#define CHUNK 16384

	/* Compress from file source to file dest until EOF on source.
	   def() returns Z_OK on success, Z_MEM_ERROR if memory could not be
	   allocated for processing, Z_STREAM_ERROR if an invalid compression
	   level is supplied, Z_VERSION_ERROR if the version of zlib.h and the
	   version of the library linked do not match, or Z_ERRNO if there is
	   an error reading or writing the files. */
int def(FILE *source, FILE *dest, int level)
{
	int ret, flush;
	unsigned have;
	z_stream strm;
	unsigned char in[CHUNK];unsigned char out[CHUNK];

	/* allocate deflate state */
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	ret = deflateInit(&strm, level);
	if (ret != Z_OK)
		return ret;

	/* compress until end of file */
	do {
		strm.avail_in = fread(in, 1, CHUNK, source);
		if (ferror(source)) {
			(void)deflateEnd(&strm);
			return Z_ERRNO;
		}
		flush = feof(source) ? Z_FINISH : Z_NO_FLUSH;
		strm.next_in = in;

		/* run deflate() on input until output buffer not full, finish
		   compression if all of source has been read in */
		do {
			strm.avail_out = CHUNK;
			strm.next_out = out;
			ret = deflate(&strm, flush);    /* no bad return value */
			assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
			have = CHUNK - strm.avail_out;
			if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
				(void)deflateEnd(&strm);
				return Z_ERRNO;
			}
		} while (strm.avail_out == 0);
		assert(strm.avail_in == 0);     /* all input will be used */

		/* done when last data in file processed */
	} while (flush != Z_FINISH);
	assert(ret == Z_STREAM_END);        /* stream will be complete */

	/* clean up and return */
	(void)deflateEnd(&strm);
	return Z_OK;
}

/* Decompress from file source to file dest until stream ends or EOF.
   inf() returns Z_OK on success, Z_MEM_ERROR if memory could not be
   allocated for processing, Z_DATA_ERROR if the deflate data is
   invalid or incomplete, Z_VERSION_ERROR if the version of zlib.h and
   the version of the library linked do not match, or Z_ERRNO if there
   is an error reading or writing the files. */
int inf(FILE *source, FILE *dest)
{
	int ret;
	unsigned have;
	z_stream strm;
	unsigned char in[CHUNK];
	unsigned char out[CHUNK];

	/* allocate inflate state */
	strm.zalloc = Z_NULL;
	strm.zfree = Z_NULL;
	strm.opaque = Z_NULL;
	strm.avail_in = 0;
	strm.next_in = Z_NULL;
	ret = inflateInit(&strm);
	if (ret != Z_OK)
		return ret;

	/* decompress until deflate stream ends or end of file */
	do {
		strm.avail_in = fread(in, 1, CHUNK, source);
		if (ferror(source)) {
			(void)inflateEnd(&strm);
			return Z_ERRNO;
		}
		if (strm.avail_in == 0)
			break;
		strm.next_in = in;

		/* run inflate() on input until output buffer not full */
		do {
			strm.avail_out = CHUNK;
			strm.next_out = out;
			ret = inflate(&strm, Z_NO_FLUSH);
			assert(ret != Z_STREAM_ERROR);  /* state not clobbered */
			switch (ret) {
			case Z_NEED_DICT:
				ret = Z_DATA_ERROR;     /* and fall through */
			case Z_DATA_ERROR:
			case Z_MEM_ERROR:
				(void)inflateEnd(&strm);
				return ret;
			}
			have = CHUNK - strm.avail_out;
			if (fwrite(out, 1, have, dest) != have || ferror(dest)) {
				(void)inflateEnd(&strm);
				return Z_ERRNO;
			}
		} while (strm.avail_out == 0);

		/* done when inflate() says it's done */
	} while (ret != Z_STREAM_END);

	/* clean up and return */
	(void)inflateEnd(&strm);
	return ret == Z_STREAM_END ? Z_OK : Z_DATA_ERROR;
}

/* report a zlib or i/o error */
void zerr(int ret)
{
	fputs("zpipe: ", stderr);
	switch (ret) {
	case Z_ERRNO:
		if (ferror(stdin))
			fputs("error reading stdin\n", stderr);
		if (ferror(stdout))
			fputs("error writing stdout\n", stderr);
		break;
	case Z_STREAM_ERROR:
		fputs("invalid compression level\n", stderr);
		break;
	case Z_DATA_ERROR:
		fputs("invalid or incomplete deflate data\n", stderr);
		break;
	case Z_MEM_ERROR:
		fputs("out of memory\n", stderr);
		break;
	case Z_VERSION_ERROR:
		fputs("zlib version mismatch!\n", stderr);
	}
}

/* compress or decompress from stdin to stdout */
int main(int argc, char **argv)
{
	int ret;

	/* avoid end-of-line conversions */
	SET_BINARY_MODE(stdin);
	SET_BINARY_MODE(stdout);

	/* do compression if no arguments */
	/* Warning: Not compatible with plain libz, dial it back down to
	 * 9 if this is required, uber-level is 10
	 * since we have everything crammed in miniz, we don't depend on
	 * libz at all.
	 */
	if (argc == 1) {
		ret = def(stdin, stdout, MZ_UBER_COMPRESSION);
		if (ret != Z_OK)
			zerr(ret);
		return ret;
	}

	/* do decompression if -d specified */
	else if (argc == 2 && strcmp(argv[1], "-d") == 0) {
		ret = inf(stdin, stdout);
		if (ret != Z_OK)
			zerr(ret);
		return ret;
	}

	/* otherwise, report usage */
	else {
		fputs("zpipe usage: zpipe [-d] < source > dest\n", stderr);
		return 1;
	}
}